Apple's SMS replacement protocol, called iMessages, lets you send free text messages between iPhones, which is great. What's not so great is that a lot of users have been experiencing iMessage lag involving long delays receiving new messages. If that sounds familiar to you, the New York Times' Brian X. Chen has a possible fix:

After it happened to me a fourth time, I complained about it on Twitter, and one of my followers came forward with a possible fix: uninstall Messages Beta, an early version of iMessage for the Mac that Apple released in February. Some of my friends and I have done just that and haven't experienced the problem since.

I haven't experienced the iMessage bug so I haven't been able to test this fix, but if you've had this problem, it's worth a try.